The objective of this project is to characterize the biophysical properties of human lenses and elucidate the mechanisms invovled in the development of lens fluorescence, pigmentation, aging and brown cataracts. We are studying fluorescence in the lens (human and rat) and fluorescent peptides and fluorescent compounds derived from normal lenses and from brown nuclear cataracts. Our biophysical approach utilizes non-destructive, non-invasive spectroscopic methods (fluorescence and phosphorescence spectra and decay, optical absorption and transmission, ESR and Raman) for comparing and contrasting the properties of young and old normal lenses and cataractous lenses. We are correlating the results of these investigations with similar studies on specific proteins and fluorescent peptides derived from these lenses in order to compare the whole lens with the sum of its component structural proteins. We are also currently defining the photoreaction products derived from UV-exposed lenses and lens proteins, both directly and in the presence of the sensitizer 8-MOP. These methods involve derivatization and GC mass spectrometry as well as NMR spectroscopy.